The operation "went very well," Dr. Patrick Walsh told reporters at a hospital news conference. Walsh said an inspection of the prostate following its removal showed the cancer "looked completely contained," but an additional microscopic analysis will be performed and should be complete in a few days.

The doctor, who is chief of urology at Johns Hopkins, also said "nothing suspicious" was found in the senator's lymph nodes.

Kerry's wife, Teresa Heinz Kerry, said the senator "is in good spirits and in great hands."

"I think John is the type of person that does well in battle," she told reporters. Kerry, the junior senator from Massachusetts, announced in December his candidacy for the White House, and he said Tuesday he does not believe his prostate cancer will hurt his campaign.

Kerry, 59, had a spinal anesthetic for the surgery. Walsh said Kerry will be walking tomorrow and should be out of the hospital on Saturday.

"The bottom line is everything went well," he said.

Noting that Kerry's father was diagnosed with prostate cancer at the age of 75 and died 10 years later, Walsh called the presidential hopeful a "poster boy" for PSA testing, saying the senator's cancer was found at an early and curable stage.

"Prostate is actually more heritable than breast or colon cancer," he said.

The PSA, or prostate specific antigen, is a protein made by the prostate that naturally leaks out into the bloodstream. The PSA test measures the level of that protein in the blood, with a raised PSA level sometimes indicating prostate cancer.

Kerry disclosed his cancer Tuesday, saying doctors discovered a localized tumor on his prostate in December. He said he does not expect the surgery to have any impact on his bid for the White House.